The Effect Of Diabetes Mellitus On The Nhs

Diabetes mellitus (more commonly known as diabetes) is a group of chronic diseases which cause a person s blood glucose level to become too high this is called hyperglycemia. There are two main types of diabetes: Types 1 and 2. Type 1 diabetes is an autoimmune disease. This is when the body s immune system, which is normally meant to help defend against diseases and infections, attacks your own body cells instead. In Type 1 diabetes, the immune system destroys cells that produce insulin in the pancreas. Less glucose is moved into the cells for respiration as a result and less glucose is turned into glycogen for storage. Hence, the blood glucose concentration remains too high. Consequently, the body breaks down fats to release energy but, in the process, it releases chemicals called ketones into the blood. High amounts of these chemicals cause the blood to turn very acidic leading to ketoacidosis which can cause a coma or death. Type 2 diabetes is the result of the inability of body cells to react to the insulin produced (insulin resistance), or the result of inadequate insulin production by the pancreas. Type 2 diabetes is much more common In the UK, 90% of all adults with diabetes have type 2 diabetes.1 Type 2 sufferers are often obese, and research has shown that fat cells are more resistant to insulin as opposed to muscle cells. Therefore, the same amount of insulin will have a lesser effect on fat cells compared to muscle cells, eventually leading to the same complications that people with type 1 diabetes have. However, the complications listed above are only a direct cause of diabetes, in reality diabetes causes a plethora of other complications, the main one being cardiovascular disease (in particular coronary heart disease.)

How can Diabetes Mellitus cause coronary heart disease and how much does it cost the NHS?

If someone with diabetes does not take their medication, high amounts of glucose will be present in their blood. High levels of glucose in the blood will reduce the production of nitric oxide a molecule made by the body which signals the blood vessels to dilate causing them to enlarge. However, if nitric oxide production is inhibited, then the blood vessels will narrow leading to a higher blood pressure. High blood pressure (or hypertension) can cause damage to the walls of arteries, thereby making it easier for fatty deposits to build up otherwise known as an atheroma. If these atheroma s build up in the coronary arteries, then then risk of having myocardial infarction or angina will increase. Hence, people with diabetes have a larger risk of developing coronary heart disease and this is putting an increasing strain on the NHS, which spends £10 billion2 on the disease each year. This accounts for roughly 9% of the budget per annum. However, 80% of these costs are due to complications such as heart disease and strokes in fact, it has been proven that over 70% of people over the age of 65 with diabetes mellitus will die with some form of heart disease or stroke.3 Therefore, it is clear to see the large and widespread effect diabetes can have on your body.

What are the current medical and revascularization strategies to treat the cardiovascular symptoms of Diabetes Mellitus and how effective are they?

The first main strategy that was proposed was intensive glycemic control. Intensive glycemic control involves pushing down Hb A1C levelsdown to 6% or less (which is the level that people without diabetes have.) The Hb A1C refers to the amount of glycated haemoglobin in the body and the percentage of Hb A1C shows the average blood glucose for the past few months. It was previously believed that achieving normal levels of glycemic control (i.e. achieving typical levels of blood sugar) would reduce the risk of having cardiovascular diseases and would also reduce the risk of mortality in both types of diabetes. For patients with Type 1 diabetes, this strategy has proved to be very beneficial with data from the Stockholm diabetes intervention study showing that tight control slows down the development of atherosclerosis4. Recently however, two large-scale studies into the effect of intensive glycemic control on patients with Type 2 diabetes have shown that the risk of cardiovascular disease (in particular coronary heart disease) has, rather surprisingly, not been reduced. The first of these trials, the ACCORD (Action to control cardiovascular disease in diabetes) trial involved 10,251 participants who had the average age of 62 years. The average baseline HB A1C levels for these participants was 8.1%5 clearly showing that they had diabetes. These participants were split into two groups: the first group received intensive treatment with target Hb A1C levels below 6% whereas the second group received standard treatment with target Hb A1C levels of 7 to 7.9%. The results from this study were unexpected with a 35% higher rate death due to cardiovascular diseases in the intensive control group over an average treatment period of 3.5 years. This study was then halted due to the increasing fatality rate.

The ADVANCE (Action in Diabetes and Vascular Disease) trial involved 11,140 participants with Type 2 diabetes and an average age of 66. This trial showed no effect on the cardiovascular risk. However, it is crucial to note the average ages of the participants in these two trials: 62 and 66. They were generally people who had diabetes for a longer period of time and so were at a higher risk of cardiovascular diseases prior to the trial occurring. In contrast a study created by UKPDS6 (United Kingdom Prospective Diabetes Study) involving 4,000 participants who were slightly younger and had diabetes for a shorter period of time, showed a direct correlation between Hb A1C levels and reduced risk of all cardiovascular diseases including coronary heart disease. However, the reliability of the results obtained is questionable as the intensive group had target Hb A1C levels which were similar to the standard group of the participants in the ACCORD and ADVACNCE trial. In conclusion, the intensive glycemic control strategy is particularly effective in reducing the risk of cardiovascular risk in Type 1 diabetes but overall, showed no effect on patients with Type 2 diabetes. Moreover, it can be said that the general targets of Hb A1C levels of 6.5% or less should remain constant as if they are not low enough then the direct complications of diabetes mentioned earlier in this article can occur but if they are too low then hypoglycaemia and increased risk of cardiovascular diseases can occur.

A second strategy to treat the cardiovascular symptoms of diabetes mellitus is surgery. Patients who have diabetes and coronary artery disease (CAD) are at a higher risk of cardiovascular events such as myocardial infarctions when compared to those without these conditions. A trial conducted by BARI 2D investigated a hypothesis stating that in patients with stable diabetes and stable CAD (a history of myocardial infarction or the presence of plaque in the arteries, but no current symptoms or symptoms controlled by medications), prompt revascularisation would reduce the long-term deaths. The study found that bypass surgery is superior to percutaneous intervention in most diabetic patients with multi vessel CAD7. Bypass surgery involves using a blood vessel from an arm or leg to bypass a narrowed segment of your coronary artery. Percutaneous intervention is a non-surgical procedure where a stent is placed to open up the narrowed artery. Both of these surgeries have had considerably better results at treating the cardiovascular symptoms of diabetes patients than intensive glycemic control and on the whole the results state that the risks of these surgeries outweigh the benefits suggesting that they are effective treatment options.

Will these treatments help reduce the cost of diabetes to the NHS in the future?

The cost of diabetes for the NHS is undoubtedly expected to rise. Diabetes is projected to cost £39.8 billion overall by 2035/36 8 and this is expected to account for 17% of the NHS budget, 8% more than today. Treatments such as these (intensive glycemic control for Type 1 diabetes and surgery for Type 2 in general) will certainly help reduce the cost of complications due to diabetes for the NHS. They will also reduce the risk of cardiovascular diseases and it should result in fewer deaths occur due to coronary heart disease, the world s leading killer.

References:

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